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A new nanotechnology approach could mean cheaper solar cells than current silicon-based approaches...
From MIT Tech Review:
Researchers at the University of California, Berkeley, have made a new kind of solar cell by growing an array of upright nanoscale pillars on aluminum foil. They make bendable solar cells by encapsulating the entire cell inside a transparent, rubbery polymer. The design, the researchers suggest, could lead to solar cells that cost less than conventional silicon photovoltaics.
Cheap solar: A new solar cell is composed of an array of erect cadmium sulfide nanopillars (bottom) embedded inside a matrix of cadmium telluride. The entire cell, fabricated on thin aluminum foil, becomes bendable when encased in polymer.
Credit: Ali Javey, UC Berkeley
The nanopillars allow the researchers to use cheaper, lower-quality materials than those used in conventional silicon and thin-film technologies. What's more, the technique used to make the cells could be adapted to make rolls of flexible panels on thin aluminum foil, cutting manufacturing costs, says Ali Javey, an electrical-engineering and computer-sciences professor who led the work. The work is at an early stage, and "you won't know the cost until you do this using a roll-to-roll process," he says. "But if you can do it, the cost could be 10 times less than what's used to make silicon panels."
The solar cells are made of uniform 500-nanometer-high pillars of cadmium sulfide embedded in a thin film of cadmium telluride. Both materials are semiconductors used in thin-film solar cells. In an online Nature Materials paper, Javey and his colleagues showed that the cells have an efficiency of about 6 percent in transforming sunlight into electricity. Others have made cells with pillar designs, he says, but they used expensive methods to grow the pillars and could not get efficiencies above 2 percent.
Harvard University chemistry professor Charles Lieber has made nanowires consisting of a silicon core and different concentric silicon layers. Peidong Yang, a chemistry professor at UC Berkeley, has made dye-sensitized solar cells with zinc oxide nanowires. These nanowire solar cells have reached efficiencies of 4 percent.
Trying other semiconductor materials might also be important given cadmium's toxicity issues, Berkeley's Yang points out. Nevertheless, he says, "architecture is most important--materials we can continue working on. The beauty of this paper is the demonstration of how well the architecture works."
More at:
http://www.technologyreview.com/computing/22958/?nlid=2172&mc_cid=6b453aa10e&mc_eid=6666b671e7
Hat tip to Southern Growth Forum |
